The present invention is related to storage media. More particularly, the present invention is related to systems and methods for preparing servo data on a storage medium.
A typical digital magnetic storage medium includes a number of storage locations where digital data may be stored. Data is written to the medium by positioning a read/write head assembly over the medium at a selected location, and subsequently passing a modulated electric current through the head assembly such that a corresponding magnetic flux pattern is induced in the storage medium. To retrieve the stored data, the head assembly is positioned anew over the track. In this position, the previously stored magnetic flux pattern induces a current in the head assembly that can be converted to the previously recorded digital data.
The storage locations on the magnetic storage medium are typically arranged as a serial pattern along concentric circles known as tracks. FIG. 1 shows a storage medium 100 with two exemplary tracks 150, 155 as dashed lines. The tracks are segregated by servo data written within wedges 160, 165. These wedges include data and supporting bit patterns that are used for control and synchronization of the head assembly over a desired storage location on storage medium 100. The data and supporting bit patterns used to derive the control and synchronization is depicted as a pattern 110 that includes a preamble 152, a sync 154, a gray code 156 and a burst 158. It should be noted that while two tracks and two wedges are shown, hundreds of each would typically be included on a given storage medium.
Traditionally, the servo data within wedges 160, 165 has been written by an external servo writer which is costly both in terms of equipment and time. In some cases, disk drive manufacturers have utilized the read/write head assembly to write the servo data using a process known as self servo writing. As one example of this process, an external writer is used to write servo data for only a limited number a tracks at an outer edge 190 of storage medium 100. Using this as a guide, the head assembly can then be used to write the servo data corresponding to the inner tracks. As another example, a reference pattern is applied more generally to storage medium 100 in a known way, but not corresponding directly to wedges 160, 165. While both approaches offer viable alternatives to the traditional approach, each requires additional capability for positioning the head assembly.
Hence, for at least the aforementioned reasons, there exists a need in the art for advanced systems and methods for head assembly positioning during self servo writing.